The present application claims the benefit of U.S. Provisional Application Ser. No. 60/357,485 filed Feb. 15, 2002, the entire text of which is herein incorporated by reference.
1. Field of the Invention
The present invention is directed to the fields of molecular biology, gene therapy, and treatment of viral disease. More specifically, the present invention relates to methods of treatment of adenoviral infection and disease, to improved methods for expressing transgenes introduced into cells with adenoviral and related vectors, and improved methods of gene therapy utilizing such methods.
2. Description of Related Art
Wild-type adenoviruses are associated with a variety of human diseases including respiratory, ocular, and gastrointestinal infections. These infections are a major cause of school absenteeism for children and of loss of work productivity for adults. In immuno-compromised individuals, infection with adenovirus currently has no effective antiviral treatment and is frequently fatal. Adenovirus infections may thus be lethal to immunocompromised patients who have received chemotherapy, bone marrow transplants, other organ transplants, or suffer from AIDS. Pediatric bone marrow transplant patients are particularly susceptible, with 10–30% developing adenovirus infection.
There are no anti-viral compounds that are effective against adenovirus infections. Thus, there is a need in the art to develop an effective treatment for adenoviral infection, especially for immunocompromised individuals.
In contrast, non-pathogenic replication-defective adenoviral vectors are useful for many preclinical and clinical gene therapy applications. Human gene therapy is an approach to treating human disease that is based on the modification of gene expression in cells of the patient. It has become apparent over the last decade that the single most outstanding barrier to the success of gene therapy as a strategy for treating inherited diseases, cancer, and other genetic dysfunctions is the development of useful gene transfer and expression vehicles. Eukaryotic viruses have been employed as vehicles for somatic gene therapy. Among the viral vectors that have been cited frequently in gene therapy research are adenoviruses.
Modified adenoviruses that are replication incompetent and therefore non-pathogenic are being used as vehicles to deliver therapeutic genes for a number of metabolic and oncologic disorders. These adenoviral vectors may be particularly suitable for disorders such as cancer that would best be treated by transient therapeutic gene expression since the DNA is not integrated into the host genome and the transgene expression is limited. Adenoviral vector may also be of significant benefit in gene replacement therapies, wherein a genetic or metabolic defect or deficiency is remedied by providing for expression of a replacement gene encoding a product that remedies the defect or deficiency.
Adenoviruses can be modified to efficiently deliver a therapeutic or reporter transgene to a variety of cell types. Recombinant adenoviruses types 2 and 5 (Ad2 and AdV5, respectively), which cause respiratory disease in humans, are among those currently being developed for gene therapy. Both Ad2 and AdV5 belong to a subclass of adenovirus that are not associated with human malignancies. Recently, the hybrid adenoviral vector AdV5/F35 has been developed and proven of great interest in gene therapies and related studies (Yotnda et al., 2001).
Recombinant adenoviruses are capable of providing extremely high levels of transgene delivery. The efficacy of this system in delivering a therapeutic transgene in vivo that complements a genetic imbalance has been demonstrated in animal models of various disorders (Watanabe, 1986; Tanzawa et al., 1980; Golasten et al., 1983; Ishibashi et al., 1993; and S. Ishibashi et al., 1994). Indeed, a recombinant replication defective adenovirus encoding a cDNA for the cystic fibrosis transmembrane regulator (CFTR) has been approved for use in at least two human CF clinical trials (Wilson, 1993). Hurwitz, et al., (1999) have shown the therapeutic effectiveness of adenoviral mediated gene therapy in a murine model of cancer (retinoblastoma).
Unfortunately, adenoviral vectors, although effective at transducing target cells, do not necessarily result in the desired level of expression of the transgene in the target cells and tissues. An exception has been noted in the ocular environment where relatively high levels of transgene expression have been observed.
There is therefore a need for effective treatment of wild type adenoviral infection, especially in immunocompromised individuals. There is also a need for methods and compositions that are effective in enhancing the expression of transgenes introduced into a wide variety of cell types and tissue.